World Cassowary Day is a day of celebration to draw international attention to the reasons cassowaries are globally important and need to be protected.
The cassowaries are ratites (very large flightless birds) in the genus Casuarius, native to the tropical forests of Papua New Guinea, the Island of New Guinea and northeastern Australia.
There are three different extant species recognised today. In evolutionary terms, the flightless birds were some of the earliest types of birds to develop. The cassowary, emu, rhea, kiwi and ostrich are still around today, but others, like the moas of New Zealand and the elephant bird of Madagascar, are now extinct.
The most common of these, the Southern Cassowary, is the third tallest and second heaviest living bird, smaller only than the ostrich and emu. The other two species are the Northern Cassowary (Casuarius unappendiculatus) and Dwarf Cassowary (Casuarius bennetti), which are only found in Papua New Guinea.
Port Moresby Nature Park’s Wildlife Manager, Ishimu Bebe, says: “A lot of people love the cassowary bird because of its unique beauty. In Papua New Guinea, the cassowary is highly regarded in traditional myths as a source of life and spiritual energy. However, it is an endangered species and its future is uncertain.
“The work we do here at Nature Park is to showcase these very large endangered flightless birds. Cassowaries play a very important role in the environment as a ‘rainforest gardener’! And what we do here at Nature Park is we encourage and educate our visitors by raising awareness on the importance of the cassowary’s role in rainforest vegetation.
“The cassowary is considered a ‘keystone species’ because of its critical role in maintaining the ecological balance of the rainforest. Protecting cassowary habitat and food plants benefits many other rainforest plants and animals. Without cassowaries, some species of rainforest plants would have no means of distribution.”
The rainforest would be a very different place without cassowaries in the wet tropics and in the islands of New Guinea. Cassowaries have been recorded eating over 238 species of plants, and they play an important role in maintaining the diversity of the rainforest.
Cassowaries prefer fallen fruit to other food, but will also eat small vertebrates (such as snails and frogs, small birds and eggs), invertebrates, fungi, carrion and plants.
These huge birds are the only animals capable of distributing the seeds of more than 70 species of trees whose fruit is too large for any other forest dwelling animal to eat and relocate.
In other tropical forests around the world, there are a wide range of animals which fulfill this role, but without cassowaries, the rainforest in Northeastern Australia, Papua New Guinea and the surrounding islands of New Guinea would gradually change and become less diverse.
Cassowaries are also capable of eating fruits and seeds that would be toxic to other species. The cassowary’s digestive system (they have an unusual combination of stomach enzymes), short intestines and highly active liver may help to protect them from absorbing a harmful level of toxins from some of the fruits they eat.
Cassowaries swallow fruit whole, digesting the pulp, and passing the seeds unharmed in large piles of droppings, distributing them over large areas throughout the rainforest. A ready-made fertiliser, the droppings help many kinds of seeds to grow. Other animals sometimes feed on the seeds in cassowary droppings, helping to distribute them further.
Their role in helping to maintain the diversity of the rainforest is why cassowaries are considered a ‘keystone’ species. Protecting cassowary habitat and food plants benefits many other rainforest plants and animals.
Port Moresby Nature Park’s CEO, Michelle McGeorge, said: “I would like to encourage the community in NCD to come out to the park and recognise this day by visiting these amazing flightless birds at our Rainforest Retreat Area and learn about how important they are to our environment. Unfortunately, these flightless birds are near-extinction.
“Habitat loss and division have left the population of cassowaries on the brink of extinction. These huge birds need large amounts of land to roam in search of food and to breed. Like other species, cassowaries’ habitats have been repeatedly destroyed by the boom in residential and commercial construction of urban spaces.”